19 century northern Maine datum help...please

ouaouaron

Posted 20 May 2013 - 07:23 AM

ouaouaron

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I have three maps of Northern Maine (Aroostook county) from 1840, 1844 and 1877. I have not been able to find out what datum was used or which datum in the QGIS respository to use when georeferencing. Does anybody have experience with historic maps and there projections?

Strebe

Posted 20 May 2013 - 03:01 PM

Strebe

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United States

You should contact Cliff Mugnier for an authoritative answer. My own guesses are: The projection is likely American polyconic for all of them. Datum is problematic and unlikely to be available. The earth was known to be an ellipsoid at those earlier dates, and the first modern determinations were being made at the time, but unlikely to have been used for those maps. Perhaps they are on a spherical model. The later map could be anything.